<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .a1{
            width: 90%;
            /*height: 50px;*/
            display: flex;
            padding: 10px 0;
            background-color: red;
            flex-direction: column;
            justify-content: center;
            align-items: center;
        }
        .as1{
            width:90px ;
            height: 90px;
            background-color: aliceblue;
            border-bottom: 10px;
            margin: 10px 10px;
            display: flex;
            justify-content: center;
            align-items: center;
        }
    </style>
</head>
<body>
        <div class="a1">
            <div class="as1">1</div>
            <div class="as1">2</div>
            <div class="as1">3</div>
        </div>
</body>
</html>